enable/disable the tray icon when pref is changed (no restart needed)

src/qtgui/rclmain_w.cpp

@@ -449,13 +449,7 @@ void RclMain::init()
 	emit sortDataChanged(m_sortspec);
     }
 
-    if (prefs.showTrayIcon && QSystemTrayIcon::isSystemTrayAvailable()) {
+    enableTrayIcon(prefs.showTrayIcon);
-        m_trayicon = new RclTrayIcon(this, 
-                                     QIcon(QString(":/images/recoll.png")));
-        m_trayicon->show();
-    } else {
-        m_trayicon = 0;
-    }
 
     fileRebuildIndexAction->setEnabled(false);
     fileToggleIndexingAction->setEnabled(false);
@@ -465,6 +459,21 @@ void RclMain::init()
     periodictimer->start(1000);
 }
 
+void RclMain::enableTrayIcon(bool on)
+{
+    on =  on && QSystemTrayIcon::isSystemTrayAvailable();
+    if (on) {
+        if (nullptr == m_trayicon) {
+            m_trayicon = new RclTrayIcon(this, 
+                                         QIcon(QString(":/images/recoll.png")));
+        }
+        m_trayicon->show();
+    } else {
+        delete m_trayicon;
+        m_trayicon = 0;
+    }
+}
+
 void RclMain::setSynEnabled(bool on)
 {
     prefs.synFileEnable = on;

src/qtgui/rclmain_w.h

@@ -90,7 +90,7 @@ public:
     IndexerState indexerState() const {
         return m_indexerState;
     }
-
+    void enableTrayIcon(bool onoff);
                             
 public slots:
     virtual void fileExit();

src/qtgui/uiprefs_w.cpp

@@ -315,6 +315,7 @@ void UIPrefsDialog::accept()
 
     prefs.keepSort = keepSortCB->isChecked();
     prefs.showTrayIcon = showTrayIconCB->isChecked();
+    m_mainWindow->enableTrayIcon(prefs.showTrayIcon);
     prefs.closeToTray = closeToTrayCB->isChecked();
     prefs.showTempFileWarning = showTempFileWarningCB->isChecked() ?
         -1 : 1024;